Lipase practical

• Set up 5 water baths

  At tempo of 20, 30, 40, 50c
• Place a test tube of lipase solution

  In each water bath
• Use a 1cm³ measuring cylinder to measure out some milk

  Add it to the test tube with the indicator
• Use a 10cm³ measuring cylinder to measure out some sodium carbonate solution

  Add to the test tube, the solution will go pink as it is alkaline
• Put a thermometer in the test tube

  Place it in the water bath at 20c
• When the temp reaches 20c

  1. Remove the thermometer from the tube

  2. Use a syringe to measure out kcm³ of lipase from the 20¿ water bath
• Add the Lipase to the test tube with phenolphthalein

  Start the clock
• Stir the contents with a glass rod

  Until the solution turns colourless
• Repeat steps 3-10

  At different temps
• write a hypothesis for this practical

  the higher the temperature, the faster the rate of reaction until the optimum temperature is reached when the rate will decrease
• what equipment would you use in this practical?

  - water baths at different temperatures

  - 2cm3 syringe

  - 10cm3 measuring cylinder

  - 10 test tubes

  - thermometer

  - stirring rod

  - stop clock

  - milk

  - sodium carbonate

  - lipase

  - phenolphthalein
• what are the risks and hazards when doing this practical?

  - phenolphthalein is an irritant and is highly flammable

  - may cause irritation to eyes and a possibility of a fire
• what should you do to lower these risks?

  - wear eye protection

  - keep phenolphthalein away from naked flames
• what is the independent variable of this practical?

  temperature
• what is the dependent variable of this practical?

  time taken for solution to turn colourless
• what are the control variables of this practical?

  - volume of milk

  - volume and concentration of sodium carbonate solution

  - volume and concentration of lipase solution

  - rate of stirring
• what is the 1st step of this practical?

  1. set up 5 water baths at temperatures of 20,30,40,50 and 60oC
• what is the 2nd step of this practical?

  2. place a test tube of lipase solution in each water bath making sure the whole solution is fully immersed in water
• what is the 3rd step of this practical?

  3. in another test tube, add 4 drops of phenolphthalein indicator
• what is the 4th step of this practical?

  4. use a 10cm3 measuring cylinder to measure out 5cm3 of milk and add it to the test tube with the indicator
• what is the 5th step of this practical?

  5. use a 10cm3 measuring cylinder to measure out 8cm3 of sodium carbonate solution and add to the test tube. solution will go pink as it's alkaline. make sure to use a different measuring cylinder for each solution to prevent contamination
• what is the 6th step of this practical?

  6. put a thermometer in the test tube and place it in the water bath at 20oC. make sure the mixture reaches the same temperature as water bath
• what is the 7th step of this practical?

  7. when temperature reaches to 20oC, remove thermometer from the test tube and use 2cm3 syringe to measure out 1cm3 of lipase solution from the 20oC water bath
• what is the 8th step of this practical?

  8. add lipase solution to the test tube and start stop clock
• what is the 9th step of this pracatical?

  9. stir contents thoroughly with glass rod until solution turns colourless
• what is the 10th step of this practical?

  10. stop the stop clock and record the time in a suitable table
• what is the 11th step of this practical?

  11. repeat these steps for each temperature making sure the solutions reach the temperature of the water bath each time
• what is the 12th step of this practical?

  12. repeat whole experiment 3 more times and and calculate the mean
• what should you do to process your data?


  record data on appropriate table, calculate mean then plot a line graph where independent variable in on x axis and dependent on y axis
• 1)

  -get a block of the material with 2 holes (one for heater and one for thermometer)